Saijo Masafumi, Matsuda Toshiro, Kuraoka Isao, Tanaka Kiyoji
Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamada-oka, Suita, Osaka 565-0871, Japan.
Biochem Biophys Res Commun. 2004 Sep 3;321(4):815-22. doi: 10.1016/j.bbrc.2004.07.030.
The xeroderma pigmentosum group A protein (XPA) binds to three nucleotide excision repair (NER) factors: RPA, ERCC1, and TFIIH. XPA also binds preferentially to UV- or chemical carcinogen-damaged DNA. In this study, we prepared anti-XPA monoclonal antibodies and examined their effects on NER. Two clones inhibited cell-free NER reactions. The mode of inhibition appeared to differ; one clone inhibited both 5' and 3' incisions equally while the other inhibited the 5' incision more. The two clones inhibited the binding of XPA to RPA, ERCC1, and TFIIH. They did not inhibit the binding to damaged DNA either. These results suggest that the interaction of XPA with these NER factors is essential to the NER pathway. The epitopes of these antibodies were located outside of the binding regions for these NER factors. Steric hindrance or conformational changes of XPA brought about by the binding of anti-XPA IgG possibly cause the inhibitory effects.
着色性干皮病A组蛋白（XPA）与三种核苷酸切除修复（NER）因子结合：复制蛋白A（RPA）、切除修复交叉互补蛋白1（ERCC1）和转录因子IIH（TFIIH）。XPA还优先结合紫外线或化学致癌物损伤的DNA。在本研究中，我们制备了抗XPA单克隆抗体，并检测了它们对核苷酸切除修复的影响。两个克隆抑制了无细胞核苷酸切除修复反应。抑制模式似乎有所不同；一个克隆同等程度地抑制5'和3'切口，而另一个克隆对5'切口的抑制作用更强。这两个克隆抑制了XPA与RPA、ERCC1和TFIIH的结合。它们也不抑制XPA与损伤DNA的结合。这些结果表明，XPA与这些核苷酸切除修复因子的相互作用对核苷酸切除修复途径至关重要。这些抗体的表位位于这些核苷酸切除修复因子结合区域之外。抗XPA IgG的结合所导致的XPA的空间位阻或构象变化可能会产生抑制作用。
Zotero 插件